LCD Test Pad Extraction for Probe Contact Reliability
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Solution Overview
Problem
Conventional liquid crystal display (LCD) lighting tests face challenges due to small test pads located within the bump of the driving IC, leading to incorrect contacts and design limitations, making it difficult to perform reliable lighting tests and limiting the flexibility in selecting driving ICs.
Innovation Solution
The proposed solution involves a liquid crystal display design with a test pad connected to first and second transistors on a substrate adjacent to the display area, allowing for a larger test pad formation outside the driving IC bump, enabling easier contact with test probes and reducing pin misalignment, and providing flexibility in selecting driving ICs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the test pad is disposed within the bump of the driving IC, then the driving IC can be compactly integrated, but the test pad size becomes small causing incorrect contact with the probe
Solution Approach 1:
The test pad is extracted from the driving IC bump area and disposed separately on the substrate adjacent to the display area. This separation allows the test pad to be formed with a larger size without occupying space within the compact driving IC structure, thereby enabling reliable probe contact while maintaining driving IC integration.
2Adaptability or versatility
If the test pad is disposed within the bump of the driving IC, then the integration is compact, but design limitations occur when selecting a driving IC
Solution Approach 1:
By extracting the test pad function from the driving IC structure, the patent enables independent optimization of both components. The driving IC can be selected based on performance requirements without being constrained by test pad placement, while the test pad can be designed with appropriate size and position for reliable testing.
3Ease of operation
If the test pad is small due to being within the bump, then the driving IC area is optimized, but it becomes difficult to carry out the lighting test
Solution Approach 1:
The patent introduces an intermediate structure by disposing the test pad on the substrate adjacent to the display area, separate from the driving IC. This intermediate placement serves as a mediator that provides easy access for probe contact during lighting tests while maintaining the compact driving IC design.
Data Source
AI summary
A liquid crystal display comprises: a first substrate; a display area disposed on the first substrate; subpixels disposed in the display area; a scan driver for supplying a scan signal to scan lines connected to the subpixels; a data driver for supplying a data signal to data lines connected to the subpixels; first transistors disposed on the first substrate adjacent to one side of the display area and connected to the data lines; second transistors disposed on the first substrate adjacent to the other side of the display area and connected to the scan lines; and a test pad connected to the first transistors and second transistors.